There are numerous medical procedures in which it is desirable to re-direct a guidewire or other elongate medical device from one location to another location within the body of a human or non-human animal subject. For example, during endovascular treatment of total or near-total occlusions in arteries, a guidewire may sometimes become embedded within the wall of an artery and it then becomes desirable to re-direct the distal end of that guidewire from its position within the artery wall into the true lumen of the artery.
Chronic total occlusions (CTOs) of arteries can occur in coronary as well as peripheral arteries. It has been estimated that approximately 10% of all endovascular angioplasty procedures are currently undertaken to treat CTOs. The factor that is most determinative of whether a CTO can be successfully treated by endovascular angioplasty is the ability (or inability) to initially pass a guidewire from a position within the true lumen of the artery proximal to the CTO, through or around the CTO and then into the true lumen of the artery at a location distal to the CTO. If a guidewire can be placed in this manner, it is typically possible to then perform angioplasty and stenting over that pre-placed guidewire to successfully restore blood flow through or around the CTO.
In CTOs where the occlusive matter is soft (or where the occlusion is less than total) a guidewire can simply be pushed through the occlusive matter itself, thereby achieving the desired placement of the guidewire with the guidewire remaining within the true lumen of the artery. However, in other cases, such as where the artery is totally occluded by hard, calcified atherosclerotic plaque, the guidewire may tend to deviate to one side, causing the distal end of the guidewire to penetrate into the wall of the artery. When this occurs, the guidewire may be pushed past the obstruction while still within the artery wall. This creates a “subintimal tract” within the wall. In many cases, the guidewire may be advanced sufficiently to extend the subintimal tract past the obstruction. However, in these cases where the guidewire has been successfully been advanced past the obstruction, the distal end of the guidewire typically remains entrapped within the newly-created subintimal tract. It then becomes necessary to re-direct the distal end of the guidewire from its entrapped location within the subintimal tract into the true lumen of the artery at a location distal to the obstruction. Following successful re-entry of the guidewire into the true lumen, balloon dilation and stenting of the subintimal tract may be accomplished to create a suitable channel for antegrade arterial blood flow around the obstruction.
The prior art has included a number of true lumen re-entry devices that are potentially useable to redirect a subintimally entrapped guidewire into the true lumen of the artery. Commercial examples of such re-entry devices include the Pioneer® Catheter (Medtronic Vascular, Santa Rosa, Calif.); the OUTBACK® LTD® Re-Entry Catheter (Cordis Corporation, Miami, Fla.) and the Enteer™ Re-entry System (Covidien/eV3, Plymouth, Minn.). Other examples are described in U.S. Pat. No. 5,830,222 (Makower); U.S. Pat. No. 6,068,638 (Makower); U.S. Pat. No. 6,159,225 (Makower); U.S. Pat. No. 6,190,353 (Makower, et al.); U.S. Pat. No. 6,283,951 (Flaherty, et al.); U.S. Pat. No. 6,375,615 (Flaherty, et al.); U.S. Pat. No. 6,508,824 (Flaherty, et al.); U.S. Pat. No. 6,544,230 (Flaherty, et al.); U.S. Pat. No. 6,655,386 (Makower et al.); U.S. Pat. No. 6,579,311 (Makower); U.S. Pat. No. 6,602,241 (Makower, et al.); U.S. Pat. No. 6,655,386 (Makower, et al.); U.S. Pat. No. 6,660,024 (Flaherty, et al.); U.S. Pat. No. 6,685,648 (Flaherty, et al.); U.S. Pat. No. 6,709,444 (Makower); U.S. Pat. No. 6,726,677 (Flaherty, et al.); U.S. Pat. No. 6,746,464 (Makower); U.S. Pat. No. 8,323,261 (Kugler, et al.); U.S. Pat. No. 8,083,727 (Kugler, et al.); U.S. Pat. No. 7,938,819 (Kugler, et al.); U.S. Pat. No. 8,257,382 (Rottenberg, et al.); U.S. Pat. No. 8,353,922 (Noriega, et al.); U.S. Pat. No. 8,043,314 (Noriega, et al.)
A recent published report describes the use of a balloon occlusion technique for diverting a guidewire from a subintimal tract into the true lumen of an artery, in lieu of using a re-entry catheter. In this reported case, a 0.035 inch guidewire was initially used to form the subintimal tract that extended past an obstructive lesion. That 0.035 inch guidewire was then removed and a separate 0.018 inch guidewire was selectively advanced into the subintimal tract. A low-profile balloon catheter was then advanced over the 0.018 inch wire into the subintimal tract. The balloon was inflated to block the subintimal tract. A 0.035 inch guidewire was then advanced through the subintimal tract next to the balloon catheter. The presence of inflated balloon within the subintimal tract caused the advancing 0.035 inch guidewire to divert out of the initial subintimal tract and into the true lumen of the artery, distal to the obstruction. Although this procedure did successfully cause the 0.035 inch guidewire to re-enter the true lumen of the artery without use of a separate re-entry catheter, this procedure did involve several time consuming steps and required the use of several guidewires as well as a separate balloon catheter. Additionally, as the authors note, this procedure must be performed with caution as advancement of the 0.035 inch guidewire past the inflated balloon could result in inadvertent perforation of the artery with resultant hematoma or arteriovenous fistula formation. Jaffan A. A., et al., Balloon Occlusion Of Subintimal Tract To Assist Distal Luminal Reentry Into Popliteal Artery, J Vasc Intery Radiol. 2012 October; 23(10):1389-91.
There remains a need in the art for the development of different and improved devices and methods useable for redirecting a subintimally entrapped guidewire back into the true lumen of an artery in a safe and efficient manner.